Electronic Commerce - ecommerce
  
In a few years, it might make more sense to call it simply “commerce."
Back when money was invented, there was probably a time when people referred to "money commerce" to distinguish it from barter, which at the time just got called "commerce." But eventually, money took over...and now "money commerce" would seem silly to say.
But we're not there yet with "ecommerce." Still, you're probably very familiar with it as a concept. It’s all the transactions you make online...all the buying that takes place with the exchange of electrons rather than the passing around of physical bills and coins.